Heat exchanger



J. R. HOLMES ETAL 2,796,239

Ju ne 1s, 1.957 HEAT EXCHANGER 3 Sheets-Sheet 1 Filed Dec. 20, 1951 M- attorneys June 18, 1957 J. R. HOLMES ETAL,

HEAT EXCHANGER s Sheets-Sheet 2 Filed Dec. 20, 1951 2.! w w 1 e n I. R 5a m & 7 kg M5 W d 64 .Zw

June 18, 1957 J. R. HOLMES ETAL 2,796,239

HEAT EXCHANGER Filed Dec. 20 ,v 1951 s sheets-sheet s By I 4 I 9L attorneys States Patent HEAT EXCHANGER John Ralph Holmes, John W. Godfrey, and Robert F. Caughill, Loclrport, N. Y., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application December 20, 1951, Serial No. 262,504

1 Claim. (Cl. 257-245) Operating fluids such as oil employed in transmissions,

especially those of the automatic type, become heated to a relatively high degree during operating periods and when in this state the effectiveness thereof is somewhat impaired. Some evaporization also takes place when the oil is heated and due to the change in the viscosity thereof it becomes less eificient as a lubricant. The cooling means for transmission fluids employed heretofore have been cumbersome and difi'icult to install. This is especially true in the case of heat exchangers employed in connection with transmissions associated with motor vehicles.

One object of the present invention is to provide a heat exchanger for fluids which is of relatively simple construction and which may be readily installed on both used as well as on new housings or containers for such fluids.

Another object is to provide a heat exchanger which is Wholly contained within a cover for a housing or receptacle, thereby greatly facilitating the installation thereof.

A further object is to provide a heat exchanger for cooling the transmission fluid of a transmission mechanism which may be incorporated in the cover for the transmission housing and which may be operatively connected to the associated engine coolant circulating system.

A still further object is to provide a heat exchanger which is simple in construction, economic in manufacture, highly efficient and durable in operation.

Other and further objects will become apparent as the description progresses.

Of the drawings:

Fig. 1 is a side elevational view of an internal combustion engine having a coolant circulating system and a transmission mechanism associated therewith, said transmission having a heat exchanger mounted on the housing thereof and operatively connected to said coolant circulating system.

Fig. 2 is a plan view, partly in section, of a heat exchanger, certain parts being broken away to more clearly show certain features thereof, said view being taken substantially along line 2-2 of Fig. 1.

Fig. 3 is a sectional elevational view of the heat exchanger and a portion of the transmission housing associated therewith taken substantially along line 3-3 of Fig. 2.

Fig. 4 is a transverse sectional view taken substantially along line 4-4 of Fig. 2.

Fig. 5 is a plan view, partly in section, taken substantially along line 55 of Fig. 3 showing the coolant circulating portion of the heat exchanger.

Fig. 6 is a plan view, partly in section, of the lower portion of a modified type of heat exchanger, certain parts being brokenaway to more clearly show certain features thereof, said view being taken substantially along line 6-6 of Fig. 7.

Fig. 7 is a sectional view of the heat exchanger taken substantially along line 7-7 of Fig. 6, and

Fig. 8 is a sectional elevational view of a further modification.

Referring to the drawings, numeral 2 indicates generally an internal combustion engine of the type usually employed in automotive vehicles having a jacket 4 provided thereon for receiving a liquid coolant. Jacket 4 has connected thereto a fitting 6 which is connected to the inlet spout 8 of a coolant radiator 10 by piping connections indicated generally at 12. The return spout 14 of radiator 10 is connected to a coolant pump 16 by piping indicated generally at 18. Pump 16 is drivenby the engine 2 through a belt and pulley mechanism indi-- cated at 20. Belt and pulley mechanism 20 also drives a fan.22, which as is well known in the art, draws air" through the radiator 10.

The crank shaft, not shown, of the engine 2 is operatively connected to a transmission indicated generally at 24 having a housing 26 enclosing the operating parts thereof. The lower end of housing 26 constitutes an oil .sump as is conventional but it is closed by a cover 28 having a flat flange 30 around the perimeter thereof which abuts against a companion flange 32 provided at the lower end of said housing. A gasket 34 is provided between flanges 30 and 32 and a series of bolt 36 tightly draws the cover into sealing engagement with housing 26. Cover 28 is of dished construction as shown at 38 thereby providing a relatively extended shallow compartment or chamber 46 for the transmission fluid, such as oil, contained within housing 26.

Spaced upwardly from bottom wall 42 of chamber 40 and disposed near the top of the latter is a fiat baffle plate or first plate 44. Bafiie plate 44, as shown more particularly in Fig. 2, extends between the side walls 46 and 48 of compartment 40 and has upwardly extending flanges 50, 52, and 54 formed thereon which are secured to the said side walls and to the end wall 56 of said compartment, respectively, by brazing. The lefthand end 58 of baffle plate 44 is spaced from the end wall 60 of chamber 40 thereby providing an opening 41 through which oil may enter said chamber. The corners 62 and 64 at the opposite end of battle plate 44 are also removed to enable the fluid in casing 26 to gravitate through the openings 63 and 65, respectively, thus pro-- viding entry into the chamber 40. Extending lengthwise.

of chamber 40 and arranged in abutting relation are three fin sections 66, 67, and 68. The upper and lower curved ends of the fins of sections 66, 67, 68 are brazed to bafiie plate 44 and to the second plate or lower wall 42 of chamber 40, respectively, as shown more particularly in Fig. 4. A fourth fin section 70 extends from substan'-- tially the right-hand wall 56 of chamber 40 and like the other fin sections the fins are also brazed to both the bottom wall 42 and to baffle plate 44. The fins of sections 66, 67, 68, and 70 are thus disposed in intimate thermal contact with wall 42 and baffle plate 44 and consequently are in good heat conducting relation with respect thereto. The outer end of fin section 66 is spaced a substantial distance from end wall 60 to enable theoil deflected into chamber 40 by battle plate 44 to be distributed over the width of said chamber. The outer end of fin section 70 is spaced a shorter distance from end wall 56 as shown in Fig. 3 since a small quantity of oil will enter chamber 40 through corner openings 63 and 65. Pin sections 68 and 70 are also spaced apart forming an open chamber 72 for the oil flowing from the opposite ends of the chamber 40, as indicated by the arrows in Fig. -2.- By virtue of the. baflie plate 44,.the

oil from casing 26 is directed only to the opening 41 provided adjacent the left-hand end of chamber and the openings 63 and 65 provided adjacent the other end of said chamber. The oil is returned to the transmission 24 by means of a suction pump indicated generally at 78 through a return pipe 80 which extends from said pump to the central portion of chamber 72. A screen 82 may be provided around the open inner end of pipe 80 to prevent any foreign matter in the oil from being returned to the transmission. is secured by brazing to a flat plate 84 which in turn may be brazed to the upper surface of baffle plate 44.

Mounted beneath wall 42 of chamber 40 and extending substantially along the entire length and breadth thereof is a dished member 86 having a fiat flange 88 extending around the perimeter thereof which is secured to the said bottom wall in any suitable manner such as by brazing. By so securing member 86 to wall 42 a fluid tight seal is provided around the edges thereof. Brazed or otherwise secured to the third plate or bottom wall 90 of member 86 are three spaced baflle members 92, 94, and 96. Baflie members 92 and 96 extend transversely partially across the chamber 98 of member 86 from side wall 100 while baffle 94 extends transversely partially across chamber 98 from the opposite side wall 102 of said chamber and is disposed substantially mid-way between the said baffles 92 and 96. Side wall 100 has provided therein inlet and outlet ports 104 and 106 for a liquid coolant which may be circulated through chamber 98. Ports 104 and 106 have brazed thereto pipe fittings 108 and 110, respectively. One end of pipes 112 and 114 are connected, respectively, to fittings 108 and 110. The other ends of pipes 112 and 114 are connected to a port in jacket 4 and to the coolant circulating pump 16, respectively, as shown in Fig, 1. the fluid cooling system of engine 2, accordingly, is circulated through compartment 98 and flows in the direction of the arrows shown in Fig. 5.

The end wall 60 of chamber 40 has provided opposite an opening therein an internally tapped drain fitting 118 which normally is closed by an externally threaded plug 120.

The cover 28 including member 86 may be constructed of aluminum or of any other good heat conducting material and all of the parts thereof hereinbefore described may be secured in position by brazing.

From the foregoing description it is seen that the transmission oil from casing 26 is directed by the baflle plate 44 to openings 41, 63, and 65 causing the oil to enter the chamber 40 only at these points. The oil then flows in the direction of the arrows shown in Fig. 2 intimately engaging the fin sections 66, 67, 68 and 70, and also the bottom wall 42 and baffie plate 44 while flowing to the center chamber 72. The oil is then returned to the transmission by pump 78 through pipe 80. While the oil is thus circulating through the upper compartment 40 of the heat exchanger a coolant fluid from the engine coolant circulating system is circulated through the lower compartment chamber 98. The coolant completely fill compartment 98 and is compelled to follow a tortuous path by baflles 92, 94, and 96 as shown by arrows in Fig. 5. The coolant fluid, accordingly, during its travel through chamber 98 comes into intimate contact with the lower surface of wall 42 and rapidly absorbs the heat transmitted to the latter by the oil in chamber 40. The heated coolant is then returned to the cooling system proper associated with engine 2 by pump 16 through return pipe 114.

Figs. 6 and 7 illustrate a slightly modified type of heat exchanger. Instead of providing substantially angle shaped baflles, such as baffles 92, 94, and 96 in the lower compartment 98 of the heat exchanger, the bottom wall 90 is provided with a series of depressions 124, 126, 128, 130, and 132. These depressions form upwardly extending, projections which extend from the bottom wall 90 The inlet end of pipe 80' The coolant from of lower compartment 98 to substantially the bottom wall 42 of the upper compartment 40. Depressions 124, 126 and 132 extend transversely partially across chamber 98 from the side wall 100 thereof while depressions 126 and extend transversely partially across said compartment from the opposite wall 102 thereof. The depressions 126 and 130 are disposed between depressions 124, 128, and 128, 132, respectively, and are disposed in staggered relation as shown more particularly in Fig. 6. Except for the structure and arrangement of baflles, the construction shown in Figs. 6 and 7 is generally similar to that previously described,

Fig. 8 shows a still further modification of the present invention. Instead of brazing a dished member such as that shown at 86 to the bottom wall 42 of chamber 40, as previously described, a cover 133 may be formed with a deeper depression 134. A division plate 136 is secured in fluid tight relation, such as by brazing, to the inner surface of the side and end walls of depression 134 intermediate the top and bottom thereof, thereby dividing said depression into upper and lower compartments 138 and 140 generally similar to the compartments 40 and 98 previously described. A tapped oil drain fitting 142 is secured to end wall 143 of cover 133 opposite an opening therein in such a manner that the oil will completely drain from the associated housing as well as from compartment 138 when the plug 144 i removed. Inlet and outlet coolant parts 146 and 148 similar to parts 104 and 106, previously described, are provided in cover 133 so that a coolant may be circulated through the lower compartment 140 thereof. Pins and baffles may also be provided in compartments 138 and 140, and, except for the changes just described the device is generally similar to those shown in Figs. 1 to 7.

From the foregoing description it is seen that simplified and highly eflicient heat exchangers have been provided. In each case the entire heat exchanger is mounted in the cover for the transmission housing and therefore occupies a minimum of space and contains no connections which would in any way interfere with the operating parts of said transmission. Owing to the simplicity and the unitary nature of the heat exchangers they may be readily installed on devices now in use as well as on new installations.

While but three embodiments of the invention have been shown and described herein, it is apparent that the invention is subject to further modification and change without departing from the spirit thereof. It therefore is to be understood that it is not intended to limit the invention to the embodiments shown and described herein but only by the scope of the claim which follows.

We claim:

A heat exchanger, comprising, a relatively shallow dished member having a bottom wall and side walls, a substantially flat upper plate secured within said dished member substantially parallel to and spaced from said bottom wall to provide a first compartment within said member, a lower plate secured to said dished member substantially parallel to and spaced from said bottom wall to form with said bottom wall a second compartment adjacent to said first compartment, said upper plate having portions of opposite edges spaced from said side walls to provide inlet passages to said upper compartment for a first fluid, means providing an outlet passage in said upper plate between said inlet passages, fins within said upper compartment arranged to direct said first fluid from said inlet passages to said outlet passage, means providing an inlet and outlet for said second compartment permitting the passage of a second fluid therethrough, and spaced bafile members in said lower compartment extending transversely partially across said lower chamber alternately from opposite sides thereof to provide a tortuous passage for said second fluid.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Aylsworth Feb. 23, 1904 Daimler July 25, 1911 Ticknor Sept. 19, 1911 Ryder Dec. 1, 1925 Beebee Dec. 20, 1927 Godward Dec. 25, 1928 Larkin May 21, 1929 10 Kiep May 23, 1933 Yeager Sept. 15, 1936 6 Hild Dec. 8, 1936 Durrell et a1. June 27, 1939 Thompson Mar. 12, 1940 Belaieff et a1 Nov. 19, 1940 Arnold June 30, 1942 Adamson Aug. 3, 1943 Hild Ian. 27, 1948 Trail Nov. 16, 1948 Trumpler Mar. 14, 1950 Shaw June 13, 1950 Jones Aug. 28, 1951 Hall Dec. 4, 1951 

